482 EXPERIMENT STATION KECOED. [Vol. 3fi 



normal animals. The use of larger doses of the killed organisms caused no 

 difference as to the susceptibility. 



Experiments with rats are also described and discussed. 



The seasonal prevalence of Hypoderma bovis in 1915, together with ob- 

 servations on the terrifying effect H. bovis has upon cattle and lesions pro- 

 duced by the larva, S. Hadwen (Ann. Rpt. Ent. Soc. Ontario, 46 (1915), pp. 

 lOS-119, figs. 4 ) ■ — " The seasonal activity of H. bovis at Agassiz is from the 

 beginning of June to the beginning,- of August. The last larvsB to emerge from 

 the backs of cattle leave during the first days of July. In H. bovis the pupal 

 period averages 35 days. High temperatures shorten the pupal period. The 

 fear cattle have for H. bovis is due to the insect's persistence and manner of 

 egg laying. Hewitt's observations on the penetration of the skin by the larvre 

 of H. bovis are confirmed. The lesions caused by the larvae differ from those 

 of H. lineatiim. Older animals show more lesions than the young." 



Castration of young pigs, F. G. Asiibuook {U. S. Dept. Agr., Farmers' Bui. 

 780 (1916), pp. 6, figs. 6). — A descriptive account prepared for the farmer. 



Hog cholera {North Dakota Sta. Rpt. 1916, pp. 13-15). — Immunization ex- 

 periments with a virus from normally susceptible pigs infected by exposure 

 or injection, from serum-infected pigs which sickened in the course of a serum 

 test, from pigs injected with blood from a hyperimmune hog immediately after 

 hyperimmunization, and from hogs which escaped infection after injection 

 with blood from a hyperimmune hog but became infected by injection of virus 

 from normally susceptible pigs infected by exposure or injection are noted. The 

 results indicate that " at least the antigenic properties of a virus may be 

 seriously affected by the protective factors with which it may come in contact 

 during passage." 



Experiments to determine the relative resistance of antibodies in antihog- 

 cholera serum to various adverse influences showed that serum kept in a re- 

 frigerator for a period of six years retained its full potency at the end of the 

 period. Serum kept at room temperature (70° F.) for a period of 212 days 

 protected an S9-lb. pig by a dose of 35.6 cc, and a 74-lb. pig by a dose of 14. S cc. 

 " Serum kept at a body temperature for a period of 212 days protected a 74-lb. 

 pig by a dose of 29.6 cc, but failed to protect a 71-lb. pig by a dose of 14.22 cc." 

 Serum kept in a practically permanent frozen condition for over three months 

 was still able to protect pigs. 



It is indicated, however, that these results do not render the usual precautions 

 observed in storing and keeping serum unnecessary. 



Meeting of committee appointed to recommend best methods of vaccina- 

 tion, control, and eradication of hog cholera {Indiana Sta. Circ. 56 (1916), pp. 

 20). — Tliis circular reports in detail the proceedings at a meeting held March 

 10, 1916, of a committee appointed at the Fourth Annual Hog Cholera Con- 

 ference. 



The committee, in resolutions adopted, recommended " a more extensive edu- 

 cational campaign among veterinarians and stockmen along sanitation and vac- 

 cination lines ; the reporting of outbreaks of hog cholera and all herds that are 

 vaccinated to the state veterinarian ; the placarding of premises infected with 

 hog cholera ; the licensing of persons using hog-cholera blood for vaccinating 

 hogs; . . . the use of hog-cholera blood in doses not less than 1 cc. for the 

 simultaneous vaccination of hogs, and antihog-cholera serum in not less than 

 20 cc. doses for small pigs, and 30 cc. for pigs weighing 100 lbs., or preferably 

 40 cc. when used simultaneously; and . . . that the state veterinarian be given 

 the necessary control over the distribution of hog-cholera virus and serum, en- 

 abling him to condemn and confiscate any antihog-cholera serum or hog-cholera 

 blood that is impotent, contaminated, or dangerous, in order that he may better 



